<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- 块1的周围的margin为10px -->
<div style="margin: 10px">
块1
<!-- 块2的上边的margin为20px -->
<div style="margin-top: 20px">块2</div>
</div>
</body>
</html>